RAY TRANSCEIVING SYSTEM OF UNDERWATER FLOWMETER AND DEDUCTION METERING METHOD

Description

TECHNICAL FIELD

[0001] The present disclosure relates to equipment and methods for offshore petroleum engineering, and in particular, to underwater multi-phase flow metering equipment for offshore petroleum engineering.

BACKGROUND

[0002] Chinese patent application (publication number: CN106706047A; CN106768120A) submitted by the applicant in 2017 discloses the use of ceramic materials (first and second ceramic sealing gaskets) to seal a fluid metering channel to reduce the absorption of gamma rays, thereby improving the measurement accuracy of the three-phase flow of oil, gas and water. However, there are problems with the production and application of flow metering equipment using ceramic materials to seal a fluid metering channel. Although the ceramic materials have little resistance to the gamma rays, they have poor ductility, are difficult to process into special-shaped structures and easy to break, and cannot meet the requirements of 20-year service life and provide product reliability. CN 206 618 453 U discloses a similar prior art underwater flowmeter for multi-phase flows.

[0003] Based on the above reasons, it is particularly urgent to find a replacement solution for ceramic materials. Conventional sealing materials include steel and polyetheretherketone (PEEK). Steel has high density and will absorb too much gamma rays, making it impossible to measure, while the PEEK does not have sufficient strength to be matched with a metal sealing ring. Titanium alloy has high strength, is relatively easy to process and form, and has a density much lower than ordinary steel, making it an alternative. However, when the thickness of the titanium alloy material is excessively large, it will still largely absorb gamma rays, which is unfavorable for improving the measurement accuracy of the three-phase flow of oil, gas and water. The heavy components inside titanium alloy scatter gamma rays largely. Compared with ordinary ceramic windows or PEEK windows, titanium alloy forms an obvious Compton effect on the ray spectrum (see Chinese patent applications with publication numbers: CN107436165A and CN107331429A). The high-energy gamma ray γ_h is partially reduced to the energy level γ_l after the Compton scattering of the titanium alloy, which may coincide with the low-energy ray γ_l' emitted by the gamma source itself, resulting in the distortion of the count rate obtained by the gamma probe, which deepens as the thickness of the titanium alloy penetrated by the gamma rays increases. This requires further adjustment and optimization of the sealing structure in terms of structure and material, reducing the thickness of the titanium alloy while ensuring the compressive strength, and a solution to the influence of Compton scattering on the count rate of the probe is sought.

SUMMARY

[0004] In view of this, the present disclosure firstly provides a ray transceiving system of an underwater flowmeter, which ensures the compressive strength and reduce the absorption of gamma rays with new material/material combination and structural design.

[0005] The technical solutions are as follows:
A ray transceiving system of an underwater flowmeter includes a flowmeter body. A fluid metering channel extends through the flowmeter body. A transmitting window and a probing window positioned on both sides of the fluid metering channel are arranged on the flowmeter body. An inner end of the transmitting window and an inner end of the probing window are arranged opposite to each other and are respectively in communication with the fluid metering channel separately. A ray transmitting module is arranged in the transmitting window. A ray probing module is arranged in the probing window. The ray transmitting module transmits rays to pass through the fluid metering channel. The ray probing module probes and receives the rays passing through the fluid metering channel.

[0006] The ray transmitting module includes a radioactive source assembly, a collimator, and a first isolation seat arranged in sequence. The first isolation seat is located at the inner end of the transmitting window. The first isolation seat separates and seals the fluid metering channel and the transmitting window. An inner end face of the first isolation seat is flush with and adapted to an inner wall of the fluid metering channel.

[0007] The ray probing module includes a probe component, a pressing ring, and a second isolation seat arranged in sequence. The second isolation seat is located at the inner end of the probing window. The second isolation seat separates and seals the fluid metering channel and the probing window. An inner end face of the second isolation seat is flush with and adapted to the inner wall of the fluid metering channel.

[0008] The key lines in:
A first beryllium pad is arranged between the collimator and the first isolation seat, and the first isolation seat is made of titanium alloy.

[0009] A second beryllium pad is arranged between the pressing ring and the second isolation seat, and the second isolation seat is made of titanium alloy.

[0010] According to the above technical solution, the titanium alloy and the metal beryllium are combined, and are installed and cooperate in a new structural form. The titanium alloy which is relatively easy to process and form is used to seal the fluid metering channel, the titanium alloy and the beryllium pad are combined to bear pressure, and the beryllium pad is used to reduce absorption of gamma rays, so as to solve the problems of inconvenient processing, short service life, and low reliability caused by material (ceramic) problems.

[0011] In addition, the present disclosure continues to provide a deduction metering method of an underwater flowmeter on the basis of using the titanium alloy as a sealing material, which solves the problem of energy level coincidence caused by Compton scattering from the perspective of improving the accuracy of a gamma count rate, so as to improve the metering accuracy. The technical solutions are as follows:

[0012] A deduction metering method of an underwater flowmeter includes the following steps:

step I, arranging the above ray transceiving system of an underwater flowmeter, penetrating the fluid metering channel using any two groups of energy levels of the radioactive source assembly, and respectively obtaining gamma count rates N corresponding to a first energy level and a second energy level by the probe component;

step II, measuring a first empty tube count rate ND and a second empty tube count rate

of the two groups of energy levels under a condition of emptying the fluid metering channel, where

in a metering state, a three-phase mixed flow of oil, gas and water passes through the fluid metering channel, and a first measured count rate

and a second measured count rate

of the two groups of energy levels are measured respectively;

step III, delineating a first empty tube deduction value

and a second empty tube deduction value

on an empty tube gamma absorption spectrum; and delineating a first measured deduction value

and a second measured deduction value

on a measured gamma absorption spectrum; and

deducting and correcting the first empty tube count rate

, the second empty tube count rate

, the first measured count rate

, and the second measured count rate

respectively to obtain a first empty tube deduction count rate

, a second empty tube deduction count rate

, a first measured deduction count rate

, and a second measured deduction count rate

in sequence, where








and

step IV, calculating a gas phase content α_gas, an oil phase content α_oil, and a water phase content α_water in the multi-phase mixed flow according to the following formulas:

where

d is a distance that a gamma ray passes through the fluid metering channel;

is an absorption coefficient of a gas phase relative to a gamma ray of the first energy level;

is an absorption coefficient of an oil phase relative to the gamma ray of the first energy level;

is an absorption coefficient of a water phase relative to the gamma ray of the first energy level;

is an absorption coefficient of the gas phase relative to a gamma ray of the gas second energy level;

is an absorption coefficient of the oil phase relative to the gamma ray of the second energy level; and

is an absorption coefficient of the water phase relative to the gamma ray of the second energy level.

[0013] After Compton scattering of the high-energy gamma rays, the scattering low-energy level coincides with the original low-energy level, and the count rate will be superimposed and increased on the gamma absorption spectrum. According to the above method steps, a count rate of the original low-energy level can be obtained by deducting a count rate of the detected scattering low-energy level on the gamma absorption spectrum.

BRIEF DESCRIPTION OF THE DRAWINGS

[0014] 

FIG. 1 is a schematic structural diagram of a ray transceiving system of an underwater flowmeter;

FIG. 2 is a schematic diagram of assembly relationships of a collimator 22, a first beryllium pad 23, and a first isolation seat 24, as well as a pressing ring 32, a second beryllium pad 33, and a second isolation seat 34; and

FIG. 3 is a process diagram of deducting

corresponding to 31 keV and deducting

corresponding to 81 keV on an empty tube gamma absorption spectrum of a Ba-133 radioactive source.

DETAILED DESCRIPTION OF THE EMBODIMENTS

[0015] The following further describes the present disclosure with reference to embodiments and the accompanying drawings.

Embodiment 1:

[0016] As shown in FIG. 1 and FIG. 2, a ray transceiving system of an underwater flowmeter includes a flowmeter body 10. A fluid metering channel extends through the flowmeter body 10. The fluid metering channel is conventionally arranged as a circular hole type channel. A transmitting window and a probing window positioned on both sides of the fluid metering channel are arranged on the flowmeter body 10. An inner end of the transmitting window and an inner end of the probing window are arranged opposite to each other and are respectively in communication with the fluid metering channel separately. A ray transmitting module is arranged in the transmitting window. A ray probing module is arranged in the probing window. The ray transmitting module transmits rays to pass perpendicular to a hole center line of the fluid metering channel. The ray probing module probes and receives the rays passing through the fluid metering channel.

[0017] The ray transmitting module includes a radioactive source assembly 21, a collimator 22, and a first isolation seat 24 arranged in sequence. The first isolation seat 24 is located at the inner end of the transmitting window. The first isolation seat 24 separates and seals the fluid metering channel and the transmitting window. An inner end face of the first isolation seat 24 is flush with and adapted to an inner wall of the fluid metering channel.

[0018] The ray probing module includes a probe component 31, a pressing ring 32, and a second isolation seat 34 arranged in sequence. The second isolation seat 34 is located at the inner end of the probing window. The second isolation seat 34 separates and seals the fluid metering channel and the probing window. An inner end face of the second isolation seat 34 is flush with and adapted to the inner wall of the fluid metering channel.

[0019] A first beryllium pad 23 is arranged between the collimator 22 and the first isolation seat 24, and the first isolation seat 24 is made of titanium alloy.

[0020] A second beryllium pad 33 is arranged between the pressing ring 32 and the second isolation seat 34, and the second isolation seat 34 is made of titanium alloy.

[0021] A surface of the first isolation seat 24 facing the collimator 22 is provided with a first embedded counterbore. The collimator 22 is provided with a first top piece 221 matched with the first embedded counterbore. The first top piece 221 is provided with a beryllium sheet insertion opening. The beryllium sheet insertion opening faces a bottom of the first embedded counterbore. The first beryllium pad 23 is embedded in and matched with the beryllium sheet insertion opening. The first top piece 221 is embedded in the first embedded counterbore. A protruding end of the first top piece 221 abuts against the bottom of the first embedded counterbore. The first beryllium pad 23 abuts against the bottom of the first embedded counterbore. A collimating hole 22a penetrates through the collimator 22. A hole center line of the collimating hole 22a is perpendicular to and intersects with the hole center line of the fluid metering channel. The collimating hole 22a includes two sections, one of which has a smaller hole diameter than the other. The small hole end of the collimating hole 22a faces the radioactive source assembly 21. The large hole end of the collimating hole 22a is in communication with the beryllium sheet insertion opening and faces the first beryllium pad 23.

[0022] A surface of the second isolation seat 34 facing the pressing ring 32 is provided with a second embedded counterbore. The second beryllium pad 33 is embedded in and matched with the second embedded counterbore. The pressing ring 32 abuts both the second beryllium pad 33 and the second isolation seat 34. The second embedded counterbore includes a circular bore segment and a circular frustum bore segment. The circular bore segment is adjacent to the fluid metering channel. The circular frustum bore segment faces the pressing ring 32. The second beryllium pad 33 is embedded in the circular bore segment. An end face of the pressing ring 32 facing the second embedded counterbore is provided with a ring of pressing flange 321. The pressing flange 321 is arranged adjacent to an inner ring of the pressing ring 32. An inner ring of the pressing flange 321 is flush with the inner ring of the pressing ring 32. The pressing flange 321 is embedded in the circular frustum bore segment. An outer ring of the pressing flange 321 is adapted to and matched with a bore wall of the circular frustum bore segment. The pressing ring 32 and the pressing flange 321 are integrally formed. An arc-shaped transition is formed between an outer wall and two end faces of the outer ring of the pressing flange 321. An arc-shaped transition is formed between a large opening section and an end face are of the circular frustum bore segment to avoid stress concentration during pressure bearing and damage to the pressing ring 32 and the second isolation seat 34. An embedded end face of the pressing flange 321 abuts the second beryllium pad 33. The pressing ring 32 and the outer ring of the pressing flange 321 abut the second isolation seat 34. A thickness of the second beryllium pad 33 is greater than a thickness of the first beryllium pad 23.

Embodiment 2:

[0023] A deduction metering method of an underwater flowmeter includes the following steps.

[0024] Step I, the ray transceiving system of an underwater flowmeter according to Embodiment 1 is arranged. The fluid metering channel is penetrated using any two groups of energy levels of the radioactive source assembly 21. Gamma count rates N corresponding to a first energy level and a second energy level are respectively obtained by the probe component 31.

[0025] The radioactive source assembly 21 can use a Ba-133 radioactive source assembly. The Ba-133 radioactive source mainly has three energy levels that can be used for flow measurement, namely 31 keV, 81 keV, and 356 keV respectively. As a specific embodiment, the multi-phase flow is measured by using two energy levels of 31 keV and 81 keV of Ba-133.

[0026] Step II, a first empty tube count rate

and a second empty tube count rate

of the two groups of energy levels are measured by the probe component 31 under a condition of emptying the fluid metering channel.

[0027] In a metering state, a three-phase mixed flow of oil, gas and water passes through the fluid metering channel, and a first measured count rate

and a second measured count rate

of the two groups of energy levels are measured by the probe component 31 respectively.

[0028] Step III, a first empty tube deduction value

and a second empty tube deduction value

are delineated on an empty tube gamma absorption spectrum. A first measured deduction value

and a second measured deduction value

are delineated on a measured gamma absorption spectrum.

[0029] Specifically, the first empty tube deduction value

, the second empty tube deduction value

, the first measured deduction value

, and the second measured deduction value

are calculated by the following method.

[0030] Deduction ranges are delineated corresponding to the first energy level and the second energy level on the empty tube gamma absorption spectrum and the measured gamma absorption spectrum respectively. The deduction range includes two deduction lines perpendicular to an abscissa axis of the gamma absorption spectra. The two deduction lines are on both sides of peak values of the corresponding energy levels. Intersection points of the two deduction lines and the abscissa axis of the corresponding gamma absorption spectra are

and

respectively. Intersection points of the two deduction lines and spectral lines of the corresponding gamma absorption spectra are

and

respectively.

[0031] The first empty tube deduction value

is a trapezoidal or rectangular area enclosed by four points

, and

delineated corresponding to the first energy level on the empty tube gamma absorption spectrum.

[0032] The second empty tube deduction value

is a trapezoidal or rectangular area enclosed by four points

, and

delineated corresponding to the second energy level on the empty tube gamma absorption spectrum.

[0033] The first measured deduction value Sx is a trapezoidal or rectangular area enclosed by four points

, and

delineated corresponding to the first energy level on the measured gamma absorption spectrum.

[0034] The second measured deduction value

is a trapezoidal or rectangular area enclosed by four points

, and

delineated corresponding to the second energy level on the measured gamma absorption spectrum.

[0035] The first empty tube count rate

, the second empty tube count rate

, the first measured count rate

, and the second measured count rate Nx are deducted and corrected respectively to obtain a first empty tube deduction count rate

, a second empty tube deduction count rate

, a first measured deduction count rate

, and a second measured deduction count rate

in sequence.

[0036] FIG. 3 shows a process diagram of deducting

corresponding to the first energy level (31 keV) and deducting

corresponding to the second energy level (81 keV) on the empty tube gamma absorption spectrum of the Ba-133 radioactive source. The two deduction lines are artificially set. After the deduction lines are artificially set,

, and

are all constants, and the setting position of the deduction line has a small influence on the metering result to a certain extent, but within an acceptable level. The first energy level (31 keV) on the empty tube gamma absorption spectrum is taken as an example.

measured by the probe component 31 actually includes two parts:

and

.

is a gamma count rate probed by the probe component 31 of the first energy level (31 keV) gamma rays emitted by Ba-133 itself after passing through the empty tube.

is probed by the probe component 31 after higher energy level rays (such as part of the 81 keV energy level rays) transmitted by Ba-133, which is reduced to 31 keV after Compton scattering, pass through the empty tube, and this part is superimposed on the empty tube gamma absorption spectrum as the first energy level (31 keV) rays transmitted by Ba-133 itself, resulting in distortion of the 31 keV gamma empty tube absorption count rate probed by the probe component 31.

[0037] Similarly:

is deducted corresponding to the second energy level (81 keV) on the empty tube gamma absorption spectrum,

is deducted corresponding to the first energy level (31 keV) on the measured gamma absorption spectrum, and a process of deducting

corresponding to the second energy level (81 keV) on the measured gamma absorption spectrum is consistent with the above situation.

[0038] Step IV, a gas phase content α_gas, an oil phase content α_oil, and a water phase content α_water in the multi-phase mixed flow are calculated according to the following formulas:



where:
d is a distance that a gamma ray passes through the fluid metering channel, namely, a diameter of the fluid metering channel.

is an absorption coefficient of a gas phase relative to a gamma ray of the first energy level, which is a constant.

is an absorption coefficient of an oil phase relative to the gamma ray of the first energy level, which is a constant.

is an absorption coefficient of a water phase relative to the gamma ray of the first energy level, which is a constant.

is an absorption coefficient of the gas phase relative to a gamma ray of the gas second energy level, which is a constant.

is an absorption coefficient of the oil phase relative to the gamma ray of the second energy level, which is a constant.

is an absorption coefficient of the water phase relative to the gamma ray of the second energy level, which is a constant.

Embodiment 3:

[0039] The metering method of Embodiment 2 is used to deduct and meter the test multi-phase mixed flow to obtain a deducted water content

, and the traditional metering method is used to obtain a distorted water content

, which is compared with a real water content

of the test multi-phase mixed flow. A deducted water content metering error W₁ and a distorted water content metering error W₂ are calculated. The only difference between the traditional metering method and Embodiment 2 is: the traditional metering method does not include step III, and the following formulas are used to calculate the distorted water content

, a distorted oil content

, and a distorted gas content

:

[0040] The water content metering error W₁ and the distorted water content metering error W₂ are calculated according to the formulas:


and

[0041] Data such as the real water content of the 5 groups of test multi-phase mixed flows randomly selected for comparison in the test process is shown in Table 1:

Table 1. Data table of real water content of test multi-phase mixed flow

	Liquid volume	Gas volume			Temperature	Pressure
Unit	m3/d	Sm3/d	%	%	Deg.C	kPa
Group 1	845.74	0.00	80.10	0.00	23.71	128.87
Group 2	868.12	0.00	74.79	0.00	23.80	127.87
Group 3	852.34	522.27	75.00	31.98	24.11	133.87
Group 4	1696.84	0.00	100.00	0.00	22.02	158.87
Group 5	1152.62	927.69	29.88	34.00	22.91	159.87

[0042] The calculated deducted water content

, distorted water content

, deducted water content metering error W₁, and distorted water content metering error Wz of the 5 groups of test multi-phase mixed flows corresponding to Table 1 are shown in Table 2:

Table 2. Water content and water content metering error of test multi-phase mixed flow

				W2	W1
Unit	%	m3/d	Sm3/d	%	%
Group 1	80.10	75.20	79.80	-4.90	-0.30
Group 2	74.79	69.40	76.20	-5.39	1.41
Group 3	75.00	67.40	73.50	-7.60	-1.50
Group 4	100.00	96.30	99.80	-3.70	-0.20
Group 5	29.88	18.40	31.80	-11.48	1.92

[0043] It can be seen from Table 2 that using the deduction algorithm of Embodiment 2, the deducted water content

obtained by metering is relatively adjacent to the real water content

, and the corresponding metering error (deducted water content metering error) is less than that of the traditional algorithm without deduction (distorted water content metering error).

[0044] The beneficial effects of the present disclosure are shown in the following two aspects: on one hand, it is reflected in the structure. The titanium alloy and the metal beryllium are combined, and are installed and cooperate in a new structural form. The titanium alloy which is relatively easy to process and form is used to seal the fluid metering channel, the titanium alloy and the beryllium pad are combined to bear pressure, and the beryllium pad is used to reduce absorption of gamma rays, so as to solve the problems of inconvenient processing, short service life, and low reliability caused by material (ceramic) problems. On the other hand, it is reflected in the metering method. By deducting the count rate of the scattering low-energy levels detected on the gamma absorption spectrum, it can be metered with the result closer to the real count rate, so as to avoid the great impact of the Compton scattering effect on the results of gamma ray measurement of multi-phase flow and improve the metering accuracy.

[0045] Finally, it should be noted that the above description is only a preferred embodiment of the present disclosure. Under the enlightenment of the present disclosure, those of ordinary skill in the art can make a variety of similar representations without departing from the purpose of the present disclosure and the claims, and such transformations all fall within the protection scope of the present disclosure.

Claims

1. A ray transceiving system of an underwater flowmeter, comprising a flowmeter body (10), wherein a fluid metering channel extends through the flowmeter body (10), a transmitting window and a probing window positioned on both sides of the fluid metering channel are arranged on the flowmeter body (10), an inner end of the transmitting window and an inner end of the probing window are arranged opposite to each other and are respectively in communication with the fluid metering channel, a ray transmitting module is arranged in the transmitting window, a ray probing module is arranged in the probing window, the ray transmitting module transmits rays to pass through the fluid metering channel, and the ray probing module probes and receives the rays passing through the fluid metering channel;

the ray transmitting module comprises a radioactive source assembly (21), a collimator (22), and a first isolation seat (24) arranged in sequence, wherein the first isolation seat (24) is located at the inner end of the transmitting window, the first isolation seat (24) separates and seals the fluid metering channel and the transmitting window, and an inner end face of the first isolation seat (24) is flush with and adapted to an inner wall of the fluid metering channel; and

the ray probing module comprises a probe component (31), a pressing ring (32), and a second isolation seat (34) arranged in sequence, wherein the second isolation seat (34) is located at the inner end of the probing window, the second isolation seat (34) separates and seals the fluid metering channel and the probing window, and an inner end face of the second isolation seat (34) is flush with and adapted to the inner wall of the fluid metering channel;

characterized in that

a first beryllium pad (23) is arranged between the collimator (22) and the first isolation seat (24), and the first isolation seat (24) is made of titanium alloy; and

a second beryllium pad (33) is arranged between the pressing ring (32) and the second isolation seat (34), and the second isolation seat (34) is made of titanium alloy.

2. The ray transceiving system of the underwater flowmeter according to claim 1, characterized in that a surface of the first isolation seat (24) facing the collimator (22) is provided with a first embedded counterbore, the collimator (22) is provided with a first top piece (221) matched with the first embedded counterbore, the first top piece (221) is provided with a beryllium sheet insertion opening, the beryllium sheet insertion opening faces a bottom of the first embedded counterbore, the first beryllium pad (23) is embedded in and matched with the beryllium sheet insertion opening, the first top piece (221) is embedded in the first embedded counterbore, a protruding end of the first top piece (221) abuts against the bottom of the first embedded counterbore, the first beryllium pad (23) abuts against the bottom of the first embedded counterbore, a collimating hole (22a) penetrates through the collimator (22), the collimating hole (22a) comprises one end with a large hole diameter and the other end with a small hole diameter, the small hole end of the collimating hole (22a) faces the radioactive source assembly (21), and the large hole end of the collimating hole (22a) is in communication with the beryllium sheet insertion opening and faces the first beryllium pad (23).

3. The ray transceiving system of the underwater flowmeter according to claim 1 or 2, characterized in that a surface of the second isolation seat (34) facing the pressing ring (32) is provided with a second embedded counterbore, the second beryllium pad (33) is embedded in and matched with the second embedded counterbore, and the pressing ring (32) abuts both the second beryllium pad (33) and the second isolation seat (34).

4. The ray transceiving system of the underwater flowmeter according to claim 3, characterized in that the second embedded counterbore comprises a circular bore segment and a circular frustum bore segment, wherein the circular bore segment is adjacent to the fluid metering channel, the circular frustum bore segment faces the pressing ring (32), the second beryllium pad (33) is embedded in the circular bore segment, an end face of the pressing ring (32) facing the second embedded counterbore is provided with a ring of pressing flange (321), the pressing flange (321) is arranged adjacent to an inner ring of the pressing ring (32), an inner ring of the pressing flange (321) is flush with the inner ring of the pressing ring (32), the pressing flange (321) is embedded in the circular frustum bore segment, an outer ring of the pressing flange (321) is adapted to and matched with a bore wall of the circular frustum bore segment, an embedded end face of the pressing flange (321) abuts the second beryllium pad (33), and the pressing ring (32) and the outer ring of the pressing flange (321) abut the second isolation seat (34).

5. The ray transceiving system of the underwater flowmeter according to claim 1 or 2, characterized in that a thickness of the second beryllium pad (33) is greater than a thickness of the first beryllium pad (23).

6. A deduction metering method of an underwater flowmeter, characterized by comprising the following steps:

step I, arranging the ray transceiving system of the underwater flowmeter according to any one of claims 1 to 5, penetrating the fluid metering channel using any two groups of energy levels of the radioactive source assembly (21), and respectively obtaining gamma count rates N corresponding to a first energy level and a second energy level by the probe component (31);

step II, measuring a first empty tube count rate

and a second empty tube count rate

of the two groups of energy levels under a condition of emptying the fluid metering channel, wherein

in a metering state, a three-phase mixed flow of oil, gas and water passes through the fluid metering channel, and a first measured count rate

and a second measured count rate

of the two groups of energy levels are measured respectively;

step III, delineating a first empty tube deduction value

and a second empty tube deduction value

on an empty tube gamma absorption spectrum; and delineating a first measured deduction value

and a second measured deduction value

on a measured gamma absorption spectrum; and

deducting and correcting the first empty tube count rate

, the second empty tube count rate

, the first measured count rate

, and the second measured count rate

respectively to obtain a first empty tube deduction count rate

, a second empty tube deduction count rate

, a first measured deduction count rate

, and a second measured deduction count rate

in sequence, wherein





and

step IV, calculating a gas phase content α_gas, an oil phase content α_oil, and a water phase content α_wαter in the multi-phase mixed flow according to the following formulas:

wherein

d is a distance that a gamma ray passes through the fluid metering channel;

is an absorption coefficient of a gas phase relative to a gamma ray of the first energy level;

is an absorption coefficient of an oil phase relative to the gamma ray of the first energy level;

is an absorption coefficient of a water phase relative to the gamma ray of the first energy level;

is an absorption coefficient of the gas phase relative to a gamma ray of the second gas energy level;

is an absorption coefficient of the oil phase relative to the gamma ray of the second energy level; and

is an absorption coefficient of the water phase relative to the gamma ray of the second energy level.

7. The deduction metering method of the underwater flowmeter according to claim 6, characterized in that in step III, the first empty tube deduction value

, the second empty tube deduction value

, the first measured deduction value

, and the second measured deduction value

are calculated by the following method:

delineating deduction ranges corresponding to the first energy level and the second energy level on the empty tube gamma absorption spectrum and the measured gamma absorption spectrum respectively, wherein the deduction range comprises two deduction lines perpendicular to an abscissa axis of the gamma absorption spectra, the two deduction lines are located on both sides of peak values of the corresponding energy levels, intersection points of the two deduction lines and the abscissa axis of the corresponding gamma absorption spectra are

and

respectively, and intersection points of the two deduction lines and spectral lines of the corresponding gamma absorption spectra are

and

respectively;

the first empty tube deduction value

is a trapezoidal or rectangular area enclosed by four points

, and

delineated corresponding to the first energy level on the empty tube gamma absorption spectrum;

the second empty tube deduction value

is a trapezoidal or rectangular area enclosed by four points

, and

delineated corresponding to the second energy level on the empty tube gamma absorption spectrum;

the first measured deduction value

is a trapezoidal or rectangular area enclosed by four points

, and

delineated corresponding to the first energy level on the measured gamma absorption spectrum; and

the second measured deduction value

is a trapezoidal or rectangular area enclosed by four points

, and

delineated corresponding to the second energy level on the measured gamma absorption spectrum.

Ansprüche

1. System von Unterwasser-Durchflussmessern mit Strahlenempfängern, das einen Durchflussmesserkörper (10) umfasst, wobei der Durchflussmesserkörper (10) von einem Fluidmesskanal durchzogen ist, wobei der Durchflussmesserkörper (10) mit einem Sendefenster und einem Erfassungsfenster versehen ist, die auf beiden Seiten des Fluidmesskanals angeordnet sind, wobei das innere Ende des Sendefensters und das innere Ende des Erfassungsfensters einander gegenüberliegend angeordnet und jeweils mit dem Fluidmesskanal verbunden sind,

wobei ein Strahlenemissionsmodul in dem Sendefenster montiert ist und ein Strahlendetektionsmodul in dem Detektionsfenster montiert ist, wobei das Strahlenemissionsmodul Strahlen emittiert und durch den Flüssigkeitsmesskanal hindurchgeht, und wobei das Strahlendetektionsmodul Strahlen, die durch den Flüssigkeitsmesskanal hindurchgehen, detektiert und empfängt;

wobei das Strahlungsemissionsmodul eine radioaktive Quellengruppe (21), einen Kollimator (22) und einen ersten Isolationssitz (24) umfasst, die hintereinander angeordnet sind, wobei der erste Isolationssitz (24) an einem inneren Ende des Sendefensters angeordnet ist, wobei der erste Isolationssitz (24) den Fluiddosierkanal von dem Sendefenster trennt und abdichtet, wobei die innere Endfläche des ersten Isolationssitzes (24) mit der Innenwand des Fluiddosierkanals bündig ist und an diese angepasst ist;

wobei das Strahlendetektionsmodul eine Sondenbaugruppe (31), einen Kompressionsring (32) und einen zweiten Isolationssitz (34) umfasst, die hintereinander angeordnet sind, wobei der zweite Isolationssitz (34) an einem inneren Ende des Detektionsfensters angeordnet ist, wobei der zweite Isolationssitz (34) den Fluiddosierkanal von dem Detektionsfenster trennt und abdichtet und die innere Endfläche des zweiten Isolationssitzes (34) mit der Innenwand des Fluiddosierkanals bündig ist und an diese angepasst ist;

dadurch gekennzeichnet, dass

ein erstes Berylliumkissen (23) zwischen dem Kollimator (22) und dem ersten Isolationssitz (24) vorgesehen ist, wobei der erste Isolationssitz (24) aus einer Titanlegierung besteht;

ein zweites Berylliumkissen (33) zwischen dem Kompressionsring (32) und dem zweiten Isolationssitz (34) vorgesehen ist, wobei der zweite Isolationssitz (34) aus einer Titanlegierung besteht.

2. System von Unterwasser-Durchflussmessern mit Strahlenempfängern nach Anspruch 1, dadurch gekennzeichnet, dass der erste Isolationssitz (24) mit einer ersten eingebetteten Senkung auf einer dem Kollimator (22) zugewandten Fläche versehen ist, wobei der Kollimator (22) mit einem ersten oberen Block (221) versehen ist, der zu der ersten eingebetteten Senkung passt, wobei eine Berylliumblech-Einbettungsöffnung in dem ersten oberen Block (221) vorgesehen ist, wobei die Berylliumblech-Einbettungsöffnung dem Boden der ersten eingebetteten Senkung zugewandt ist, wobei das erste Berylliumkissen (23) in die Berylliumblech-Einbettungsöffnung eingebettet ist und zu dieser passt, wobei sich der erste obere Block (221) in die erste eingebettete Senkung erstreckt, das verlängerte Ende des ersten oberen Blocks (221) auf dem Boden der ersten eingebetteten Senkung ruht, wobei das erste Berylliumkissen (23) auf dem Boden der ersten eingebetteten Senkung ruht, wobei der Kollimator (22) von Kollimationsöffnungen (22a) durchzogen ist, , wobei die Kollimationsöffnungen (22a) eine große Öffnung an einem Ende und eine kleinere Öffnung am anderen Ende aufweisen, wobei das Ende mit der kleinen Öffnung der Kollimationsöffnungen (22a) auf die Quellengruppe (21) ausgerichtet ist und das Ende mit der großen Öffnung der Kollimationsöffnungen (22a) in Verbindung mit der eingebetteten Öffnung der Berylliumplatte steht und auf das erste Berylliumkissen (23) ausgerichtet ist.

3. System von Unterwasser-Durchflussmessern mit Strahlenempfängern nach Anspruch 1 oder 2, dadurch gekennzeichnet, dass eine zweite eingebettete Senkung in der Fläche des zweiten Isolationssitzes (34) in Richtung des Kompressionsrings (32) vorgesehen ist, das zweite Berylliumkissen (33) in die zweite eingebettete Senkung eingebettet ist und in diese passt, und der Kompressionsring (32) sowohl gegen das zweite Berylliumkissen (33) als auch gegen den zweiten Isolationssitz (34) drückt.

4. System von Unterwasser-Durchflussmessern mit Strahlenempfängern nach Anspruch 3, dadurch gekennzeichnet, dass die zweite eingebettete Senkung einen runden Lochabschnitt und einen runden Tischlochabschnitt umfasst, wobei sich der runde Lochabschnitt in der Nähe des Fluidmesskanals befindet, der runde Tischlochabschnitt auf den Kompressionsring (32) ausgerichtet ist und das zweite Berylliumkissen (33) in den runden Lochabschnitt eingebettet ist, wobei der Kompressionsring (32) mit einem Ring von Kompressionsflanschen (321) an einer Endfläche zu dem zweiten eingebetteten Senkungsloch hin versehen ist, wobei die Kompressionsflansche (321) nahe dem Innenring des Kompressionsrings (32) vorgesehen sind, wobei der Innenring der Kompressionsflansche (321) mit dem Innenring des Kompressionsrings (32) bündig ist, wobei die Kompressionsflansche (321) in dem runden Tischlochabschnitt eingebettet sind, wobei der Außenring des Druckflansches (321) an die Wand der Öffnung des kreisförmigen Tischlochabschnitts angepasst ist und zu dieser passt, wobei die Endfläche des eingebetteten Endes des Druckflansches (321) das zweite Berylliumkissen (33) zusammendrückt, und wobei der Kompressionsring (32) ebenso wie der Außenring des Druckflansches (321) den zweiten Isolationssitz (34) zusammendrückt.

5. System von Unterwasser-Durchflussmessern mit Strahlenempfängern nach Anspruch 1 oder 2, dadurch gekennzeichnet, dass die Dicke des zweiten Berylliumkissens (33) größer als die Dicke des ersten Berylliumkissens (23) ist.

6. Verfahren zur deduktiven Messung eines Unterwasser-Durchflussmessers, dadurch gekennzeichnet, dass es in den folgenden Schritten durchgeführt wird:

S1. Aufbau eines Unterwasser-Durchflussmesser-Strahlungsempfängersystems nach einem der Ansprüche 1 bis 5, wobei zwei beliebige Sätze von Energieniveaus der radioaktiven Quellenbaugruppe (21) verwendet werden, um den Fluidmesskanal zu durchdringen, und die Gamma-Zählrate N der entsprechenden ersten bzw. zweiten Energieniveaus erhalten wird, die von der Sondenbaugruppe (31) erfasst werden;

S2. Unter der Bedingung, dass der Fluidmesskanal geleert wird, werden die Zählrate des ersten leeren Rohrs

und die Zählrate des zweiten leeren Rohrs

der beiden Gruppen von Energieniveaus getrennt bestimmt;

Im Messzustand fließt das Dreiphasengemisch aus Ö1, Gas und Wasser durch den Fluidmesskanal, und die erste Zählrate der Messung

und die zweite Zählrate der Messung

werden jeweils für die beiden Gruppen von Energieniveaus bestimmt;

S3. Der erste Röhrenabzug

und der zweite Röhrenabzug

werden auf dem Röhren-Gamma-Absorptionsspektrum abgegrenzt; der erste Messabzug

und der zweite Messabzug

werden auf dem Mess-Gamma-Absorptionsspektrum abgegrenzt;

Abzugskorrekturen werden an die Zählrate des ersten leeren Rohrs

und die Zählrate des zweiten leeren Rohrs

, die erste Zählrate der Messung

und die zweite Zählrate der Messung

vorgenommen, um die erste ATC-Abzugszählrate

, die zweite ATC-Abzugszählrate

, die erste Mess-Abzugszählrate

und die zweite Mess-Abzugszählrate

in dieser Reihenfolge zu erhalten;

S4. Der Gasphasengehalt α_gas, der Ölphasengehalt α_oli, und der Wasserphasengehalt α_water im Mehrphasengemisch werden nach den folgenden Gleichungen berechnet;

Darin,

d ist die Strecke, die die Gammastrahlen durch den Fluidmesskanal zurücklegen;

ist der Absorptionskoeffizient der Gammastrahlen des Gases in Bezug auf das erste Energieniveau;

ist der Absorptionskoeffizient der Gammastrahlen des Öls in Bezug auf das erste Energieniveau;

ist der Absorptionskoeffizient der Gammastrahlen für Wasser, bezogen auf das erste Energieniveau;

ist der Absorptionskoeffizient von Gammastrahlen für Gas, bezogen auf das zweite Energieniveau;

ist der Absorptionskoeffizient von Gammastrahlen für Ö1, bezogen auf das zweite Energieniveau;

ist der Absorptionskoeffizient von Gammastrahlen in Wasser, bezogen auf das zweite Energieniveau.

7. Verfahren zur deduktiven Messung eines Unterwasser-Durchflussmessers nach Anspruch 6, dadurch gekennzeichnet, dass In Schritt 3 werden der erste Röhrenabzug

und der zweite Röhrenabzug

, der erste Messabzug

und der zweite Messabzug

nach dem folgenden Verfahren berechnet:

Wobei auf dem Gamma-Absorptionsspektrum der Röhre und dem gemessenen Gamma-Absorptionsspektrum, das dem ersten Energieniveau bzw. dem zweiten Energieniveau entspricht, ein Abzugsbereich abgegrenzt wird, der zwei Abzugslinien senkrecht zur Querachse des Gamma-Absorptionsspektrums umfasst, wobei sich die beiden Abzugslinien auf beiden Seiten des Spitzenwerts des entsprechenden Energieniveaus befinden, wobei die Schnittpunkte von zwei der genannten Ableitungslinien mit den transversalen Koordinatenachsen der entsprechenden Gamma-Absorptionsenergiespektren jeweils

, und die Schnittpunkte von zwei der genannten Ableitungslinien mit den Spektrallinien der entsprechenden Gamma-Absorptionsenergiespektren jeweils

sind;

wobei der erste Röhrenabzug

eine trapezförmige oder rechteckige Fläche ist, die von vier Punkten

begrenzt wird, die dem ersten Energieniveau auf dem Gamma-Absorptionsspektrum der Luftröhre entsprechen;

der zweite Röhrenabzug

eine trapezförmige oder rechteckige Fläche ist, die von vier Punkten

begrenzt wird, die dem zweiten Energieniveau auf dem Gamma-Absorptionsspektrum der Luftröhre entsprechen;

der erste Messabzug

eine trapezförmige oder rechteckige Fläche ist, die durch vier Punkte

,

begrenzt ist, die dem ersten Energieniveau entsprechen, das auf dem gemessenen Gamma-Absorptionsenergiespektrum abgegrenzt ist;

der zweite Messabzug

eine trapezförmige oder rechteckige Fläche ist, die durch vier Punkte

begrenzt ist, die dem zweiten Energieniveau entsprechen, das auf dem gemessenen Gamma-Absorptionsenergiespektrum abgegrenzt ist;

Revendications

1. Système d'émission-réception de rayon du débitmètre sous-marin, comprenant un corps de débitmètre (10), dans lequel un canal de mesure de fluide s'étend à travers le corps de débitmètre (10), une fenêtre d'émission et une fenêtre de détection positionnées des deux côtés du canal de mesure de fluide sont disposées sur le corps de débitmètre (10), une extrémité intérieure de la fenêtre d'émission et une extrémité intérieure de la fenêtre de détection sont disposées à l'opposé l'une de l'autre et sont respectivement en communication avec le canal de mesure de fluide, un module d'émission de rayon est disposé dans la fenêtre d'émission, un module de détection de rayon est disposé dans la fenêtre de détection, le module d'émission de rayon émet des rayons afin de traverser le canal de mesure de fluide, et le module de détection de rayon détecte et reçoit les rayons traversant le canal de mesure de fluide ;

le module d'émission de rayon comprend un ensemble de source radioactive (21), un collimateur (22) et un premier siège d'isolation (24) disposés en séquence, dans lequel le premier siège d'isolation (24) est situé au niveau de l'extrémité intérieure de la fenêtre d'émission, le premier siège d'isolation (24) sépare et scelle le canal de mesure de fluide et la fenêtre d'émission, et une face d'extrémité intérieure du premier siège d'isolation (24) est à niveau avec et adaptée à une paroi intérieure du canal de mesure de fluide ; et

le module de détection de rayon comprend un composant de sonde (31), une bague de pression (32) et un second siège d'isolation (34) disposés en séquence, dans lequel le second siège d'isolation (34) est situé au niveau de l'extrémité intérieure de la fenêtre de détection, le second siège d'isolation (34) sépare et scelle le canal de mesure de fluide et la fenêtre de détection, et une face d'extrémité intérieure du second siège d'isolation (34) est à niveau avec et adaptée à la paroi intérieure du canal de mesure de fluide ;

caractérisé en ce que,

un premier tampon de béryllium (23) est disposé entre le collimateur (22) et le premier siège d'isolation (24), et le premier siège d'isolation (24) est fait d'un alliage de titane ; et

un second tampon de béryllium (33) est disposé entre la bague de pression (32) et le second siège d'isolation (34), et le second siège d'isolation (34) est fait d'un alliage de titane.

2. Système d'émission-réception de rayon du débitmètre sous-marin selon la revendication 1, caractérisé en ce que, une surface du premier siège d'isolation (24) face au collimateur (22) est pourvue d'un premier contre-alésage encastré, le collimateur (22) est pourvu d'une première pièce supérieure (221) assortie avec le premier contre-alésage encastré, la première pièce supérieure (221) est pourvue d'une ouverture d'insertion de feuille de béryllium, l'ouverture d'insertion de feuille de béryllium fait face à un fond du premier contre-alésage encastré, le premier tampon de béryllium (23) est encastré dans et assorti avec l'ouverture d'insertion de feuille de béryllium, la première pièce supérieure (221) est encastrée dans le premier contre-alésage encastré, une extrémité saillante de la première pièce supérieure (221) vient en butée contre le fond du premier contre-alésage encastré, le premier tampon de béryllium (23) vient en butée contre le fond du premier contre-alésage encastré, un trou de collimation (22a) pénètre à travers le collimateur (22), le trou de collimation (22a) comprend une extrémité d'un grand diamètre et l'autre extrémité d'un petit diamètre, l'extrémité d'un petit diamètre du trou de collimation (22a) fait face à l'ensemble de source radioactive (21), et l'extrémité d'un grand diamètre du trou de collimation (22a) est en communication avec l'ouverture d'insertion de feuille de béryllium et fait face au premier tampon de béryllium (23).

3. Système d'émission-réception de rayon du débitmètre sous-marin selon la revendication 1 ou 2, caractérisé en ce que, une surface du second siège d'isolation (34) face à la bague de pression (32) est pourvue d'un second contre-alésage encastré, le second tampon de béryllium (33) est encastré dans et assorti avec le second contre-alésage encastré, et la bague de pression (32) vient en butée à la fois contre le second tampon de béryllium (33) et contre le second siège d'isolation (34).

4. Système d'émission-réception de rayon du débitmètre sous-marin selon la revendication 3, caractérisé en ce que, le second contre-alésage encastré comprend un segment d'alésage circulaire et un segment d'alésage de tronc circulaire, dans lequel le segment d'alésage circulaire est adjacent au canal de mesure de fluide, le segment d'alésage de tronc circulaire fait face à la bague de pression (32), le second tampon de béryllium (33) est encastré dans le segment d'alésage circulaire, une face d'extrémité de la bague de pression (32) face au second contre-alésage encastré est pourvue d'un anneau de bride de pression (321), la bride de pression (321) est disposée adjacente à une bague intérieure de la bague de pression (32), une bague intérieure de la bride de pression (321) est à niveau avec la bague intérieure de la bague de pression (32), la bride de pression (321) est encastrée dans le segment d'alésage de tronc circulaire, une bague extérieure de la bride de pression (321) est adaptée à et assortie avec une paroi d'alésage du segment d'alésage de tronc circulaire, une face d'extrémité encastrée de la bride de pression (321) vient en butée contre le second tampon de béryllium (33), et la bague de pression (32) et la bague extérieure de la bride de pression (321) vient en butée contre le second siège d'isolation (34).

5. Système d'émission-réception de rayon du débitmètre sous-marin selon la revendication 1 ou 2, caractérisé en ce que l'épaisseur du second tampon de béryllium (33) est supérieure à l'épaisseur du premier tampon de béryllium (23).

6. Procédé de mesure de déduction d'un débitmètre sous-marin, caractérisé en ce qu'il comprend les étapes suivantes consistant à :

étape I: disposer le système d'émission-réception de rayon du débitmètre sous-marin selon l'une quelconque des revendications 1 à 5, pénétrer dans le canal de mesure de fluide à l'aide des deux groupes quelconques de niveaux d'énergie de l'ensemble de source radioactive (21), et obtenir respectivement des taux de comptage gamma N correspondant à un premier niveau d'énergie et à un second niveau d'énergie par le composant de sonde (31) ;

étape II : mesurer un premier taux de comptage de tube vide

et un second taux de comptage de tube vide

des deux groupes de niveaux d'énergie dans une condition de vidange du canal de mesure de fluide, dans lequel, dans un état de mesure, un flux mixte triphasique d'huile, de gaz et d'eau passe à travers le canal de mesure de fluide, et un premier taux de comptage mesuré

et un second taux de comptage mesuré

des deux groupes de niveaux d'énergie sont mesurés respectivement ;

étape III : délimiter une première valeur de déduction de tube vide

et une seconde valeur de déduction de tube vide

sur un spectre d'absorption gamma de tube vide ; et délimiter une première valeur de déduction mesurée

et une seconde valeur de déduction mesurée

sur un spectre d'absorption gamma mesuré ; et

déduire et corriger respectivement le premier taux de comptage de tube vide

, le second taux de comptage de tube vide

, le premier taux de comptage mesuré

et le second taux de comptage mesuré

afin d'obtenir un premier taux de comptage de déduction de tube vide

, un second taux de comptage de déduction de tube vide

, un premier taux de comptage de déduction mesurée

, et un second taux de comptage de déduction mesurée

en séquence, dans lequel





et

étape IV : calculer une teneur en phase gazeuse α_gas, une teneur en phase huileuse α_oil, et une teneur en phase aqueuse α_water dans le flux mixte multiphasique selon les formules suivantes :

où :

d représente une distance à laquelle un rayon gamma traverse le canal de mesure de fluide ;

représente un coefficient d'absorption d'une phase gazeuse par rapport à un rayon gamma du premier niveau d'énergie ;

représente un coefficient d'absorption d'une phase huileuse par rapport au rayon gamma du premier niveau d'énergie ;

représente un coefficient d'absorption d'une phase aqueuse par rapport au rayon gamma du premier niveau d'énergie ;

représente un coefficient d'absorption de la phase gazeuse par rapport à un rayon gamma du second niveau d'énergie ;

représente un coefficient d'absorption de la phase huileuse par rapport au rayon gamma du second niveau d'énergie ; et

représente un coefficient d'absorption de la phase aqueuse par rapport au rayon gamma du second niveau d'énergie.

7. Procédé de mesure de déduction d'un débitmètre sous-marin selon la revendication 6, caractérisé en ce que, à l'étape III, la première valeur de déduction de tube vide

, la seconde valeur de déduction de tube vide

, la première valeur de déduction mesurée

et la seconde valeur de déduction mesurée

sont calculées selon les étapes suivantes consistant à :

délimiter des plages de déduction correspondant au premier niveau d'énergie et au second niveau d'énergie sur le spectre d'absorption gamma de tube vide et sur le spectre d'absorption gamma mesuré, respectivement, la plage de déduction comprenant deux lignes de déduction perpendiculaires à un axe des abscisses du spectre d'absorption gamma, les deux lignes de déduction étant situées des deux côtés des valeurs de crête des niveaux d'énergie correspondants, des points d'intersection des deux lignes de déduction et de l'axe des abscisses du spectre d'absorption gamma correspondant étant

et

, respectivement, des points d'intersection des deux lignes de déduction et des lignes spectrales du spectre d'absorption gamma correspondant étant

et

, respectivement ;

la première valeur de déduction de tube vide

représente une zone trapézoïdale ou rectangulaire délimitée par quatre points

et

correspondant au premier niveau d'énergie sur le spectre d'absorption gamma de tube vide ;

la seconde valeur de déduction de tube vide

représente une zone trapézoïdale ou rectangulaire délimitée par quatre points

et

correspondant au second niveau d'énergie sur le spectre d'absorption gamma de tube vide ;

la première valeur de déduction mesurée

représente une zone trapézoïdale ou rectangulaire délimitée par quatre points

et

correspondant au premier niveau d'énergie sur le spectre d'absorption gamma mesuré ; et

la seconde valeur de déduction mesurée

représente une zone trapézoïdale ou rectangulaire délimitée par quatre points

et

correspondant au second niveau d'énergie sur le spectre d'absorption gamma mesuré.

Drawing